Even if liability is established there may be a dispute over allocation of fault. Arizona uses a pure comparative fault standard. This means, fault for the incident is allocated to everyone involved based on a percentage. For example, if two people run a stop sign at the same time as each other, it is equally both of their faults. This would be measured as 50% fault for each driver.
With bike accidents, fault can be partially attributed to the cyclist for not wearing their helmet (thereby making their injuries worse), acting negligently (for example operating the bike in a dangerous manner), or breaking a law (running a stop sign). Whatever fault a person is allocated is the same percentage deducted from their case. For example, if the total case value, regardless of fault, is $10,000, and the bike rider is allocated 20% fault, the rider would only be able to recover $8,000.
Insurance companies try and diminish the case by placing the fault on the injured rider. It is important to have an advocate who understands the allocation of fault, the local rules for bike riders, and preserves your rights.